PHP Mongodb driver gives "unauthorized" error when running MongoDB->execute() with Mongo 2.4.0 using authentication - mongodb-php

Question

I am having trouble with the following code:
$m = new MongoClient('mongodb://sf:xxxxxx#localhost/sf');
$collections = $m->selectDB("sf")->getCollectionNames();
var_dump($collections); // prints collection names as expected
$collections = $m->selectDB("sf")->execute('function (){ return db.getCollectionNames(); }');
var_dump($collections); // gives error "unauthorized"
This has been reproduced on:
Mongo 2.4.0 , MongoDB PHP driver 1.3.6, PHP Version 5.3.8, Windows 7 32-bit
Mongo 2.4.0 , MongoDB PHP driver 1.3.5, PHP Version 5.3.2, Ubuntu 10.04.4
Any help?

Answer 1

PHP's execute is just a wrapper to call eval which requires admin access to use.
From the documentation:
With authentication enabled, eval will fail during the operation
if you do not have the permission to perform a specified task.
Changed in version 2.4: You must have full admin access to run.

Answer 2

Check your connection string for MongoDB. If it includes the database, try removing it. For example:
mongodb://sf:[pass]#localhost/sf
to
mongodb://sf:[pass]#localhost/
After this is done, select the database after the client is instantiated with authentication. I believe this should allow you to utilize the function. I believe it results in the authentication being done for the admin collection instead of the specified collection, perhaps providing access to this function.